1. Field of the invention
This invention relates, generally, to interlockable metal-skinned modular foam panels. More particularly, it relates to a panel design including a stiffener that enables construction of very wide modules.
2. Description of the prior art
Modular panels have broad utility in the construction industry; because of their relative strength and insulating properties, they may be used in a wide variety of applications ranging from roofs for add-on rooms to walls and roofs for walk-in freezers. In their most popular form, they include a core formed of expanded polystryene (EPS) or other suitable material that is protected by a metallic skin. The skin may cover the top only of the core in some applications, or it may cover the top and bottom of the core.
Advantageously, the metal skin may also be used to interlock contiguous panels together. More particularly, it may be bent into different interlocking configurations so that contiguous panels are joined together when their respective metal skins are interlocked with one another.
All of the known designs have utility, but some of the designs include metal formations that are expensive to produce. Some of the designs are very difficult for workers in the field to assemble, and some of the easy-to-assemble designs just as easily come apart, i.e., they have poor sealing properties. Many designs leak when rained upon, even when generous amounts of caulking are applied to the seams between contiguous panels. Thus, the art has tried to develop panels that are inexpensive, easily assembled but held strongly against separation when assembled, and which do not leak.
In typical room add-on or walk-in freezer applications, the panels will be a few inches thick, perhaps eight feet in length, and about four feet in width. The metallic skins of contiguous panels are usually interlocked along their respective lengths; thus, the metal skins may interlock along an eight foot long extent, for example. When panels of greater length are made, they become unacceptably weak. Thus, if an application calls for forty foot long modular panels, for example, the conventional wisdom states that such panels cannot be of the metal skin, foam core type unless provided with additional support. One technique for providing such additional support is the provision of an embedded stiffener within the EPS at the time of manufacture. Such embedding complicates the manufacturing process and produces a heavier panel. The only known alternative to the use of embedded stiffeners is the provision of additional support structures such as additional beams for roof panels, for example. This common expediency obviously increases the cost of the structure.
If a metal skin, foam core panel free of embedded stiffening means having sufficient strength so as to require no additional support even when up to forty feet in length could be produced, it would revolutionize the art. However, when the art is viewed as a whole, it neither teaches nor suggests how such a panel could be provided.